Today | Weather | Wednesday, May 20, 2026

Weather in Redwood City, California

02:53 PM
Now
Cloudy Weather
81° F
Feels Like 84°
Precipitation 0 %
Wind 12 mph
UV Index (0 - 11+) 7
Humidity 37 %
Today
Cloudy Weather
Day 81°
Night 52°
Precipitation 0 %
Wind 8 mph
UV Index (0 - 11+) 11

Warning: Extreme UV Index Today: 11

Overexposure to the sun's harmful UV rays can cause sunburn and increase the risk of developing skin cancer, including melanoma. Protect yourself by wearing clothing that covers your skin, sunglasses, and a hat. Apply a broad-spectrum sunscreen with an SPF of 30 or higher every two hours, even on cloudy days. Minimize direct sun exposure during peak hours (10 AM to 4 PM) to reduce the risk.

Redwood City Weather Forecast Updated

Last updated on

Air Quality in Redwood City

NOW
36 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 5.55 µg/m³
PM10 18.5 µg/m³
O3 0.039 ppm
NO2 0.2 ppb
SO2 0.3 ppb
CO 0.09 ppm
NH3 0 µg/m³
NO 0.1 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)
PM2.55.55 µg/m³
PM1018.5 µg/m³
O375.63 µg/m³
NO20.34 µg/m³
SO20.84 µg/m³
CO105.78 µg/m³
NH30 µg/m³
NO0.1 µg/m³